_____seems very hard ____ this problem in an hour

ti seems very hard 什么this problem in an hour This kind of book is very popular.It （sell） out in an hour适当 This problem was very difficult.Lily couldn't ____ He ____ very hard in the ____(study). It took Jane a whole hour to ____ this algebra problem.(A) w The plane will ____ in half an hour. it is ____(not easy,hard)for me to finish half an hour 英语翻译We'd been at this thing,hard,for almost an hour,some a l I spend an hour in doing my homework.同义句（____ ____ me an hou He ____ very hard in the past few years.(study) in an hour In an hour翻译